This is the decision【 made by them.过去分词短语,后置定语】
=This the decision 【that/which was made by them定语从句】
意思,功能相同,结构不同.
记住哦——过去分词短语中,没有be动词；
表示被动的 定语从句中,要用be动词.再如：
A lake is an area of water 【surrounded by land.】
=A lake is an area of water 【which/that is surrounded by land.】
祝你开心如意!